Method and apparatus for absorbing moisture

ABSTRACT

An improved nonwoven polypropylene fabric, having the fibers on one side fused and the fibers on the opposite side unfused, which fabric when wetted exhibits a wet feeling on the fused side and a substantially dry feeling on the unfused side. Also disclosed are bandage, diaper, hat sweatband and headband or wristband structures employing the fabric as well as a method of transferring moisture from a moisture-bearing surface utilizing the fabric.

This is a division of application Ser. No. 844,350, filed Oct. 21, 1977,now abandoned.

This invention relates to nonwoven fabrics. More particularly, thisinvention relates to method and means for utilizing an improved nonwovenpolypropylene fabric.

It is desirable to provide for the removal of moisture in the form ofperspiration and the like from the skin of human beings, especiallythose involved in physical exercise. A common method of removal of suchmoisture involves the application of moisture-absorbent cloth, such ascotton terry cloth or the like, to the moist skin. The use of headbandsand wristbands of moisture-absorbent cloth is common among participantsin athletics to keep the perspiration from flowing into the eyes or ontothe hands and impairing the vision or grip of the exercising individual.Similarly, hats are commonly provided with sweatbands to absorbperspiration from the head of a hat wearer.

In the instances noted above, the moisture-absorbent headbands,wristbands and hat sweatbands normally maintain the moisture absorbedthereby in contact with the skin of the wearer which, aside from beinguncomfortable to the wearer, can restrict normal evaporation of moisturefrom the contacted skin surface which can cause irritation and promotethe development of skin rashes.

It is also desirable to absorb body liquids from infants through the useof diapers. Disposable diapers have been developed which provide adegree of moisture absorption and isolation which is superior to theconventional cloth diaper. However, it is desirable that a disposablediaper be capable of both absorbing body fluids from the perineal regionof an infant and isolating such absorbed fluids out of contact with theskin of the infant to keep the area as dry as possible and thus reducethe incidence of skin irritation and rash.

It is further desirable to absorb and isolate body fluids from a sore ora wound to maintain it in as dry a condition as possible to promoterapid healing and reduce the possibility of infection. In the past, theconventional means for accomplishing this task has involved the use ofbandages or compresses formed of moisture-absorbent cloth whichcharacteristically maintain the fluid absorbed thereby in contact withthe sore or wound thus retarding the evaporative drying of the sore orwound and retarding the healing process.

The present invention provides novel method and means for transferringmoisture in the form of perspiration, body fluid or the like from theskin of an individual which overcomes the problems noted above.

I have discovered that a nonwoven fabric, formed of staple polypropylenefibers which have been drawn, needled and fused on a single sidethereof, exhibits an unexpected and surprising property characterized inthat when such fabric is wetted, water is released through the fusedside but is not released through the unfused or beard side. Thischaracteristic or property of such a fabric is so marked that when thewetted fabric is placed against the skin the fabric feels wet on thefused side and dry on the unfused or beard side. More particularly, thefused side of the wetted fabric will wet an object in contact therewithwhile the unfused or beard side will not wet such an object contactedthereby.

The present invention provides a method of transferring moisture from amoisture-bearing surface by contacting such surface with the unfused orbeard side of a nonwoven fabric comprising a plurality of polypropylenefibers which fibers are fused on the opposite side.

The present invention further provides a moisture-absorbing structureemploying a nonwoven fabric of polypropylene fibers having a singlefused side.

In another embodiment the present invention provides a bandage structureemploying a nonwoven fabric of polypropylene fibers having a singlefused side in the construction thereof.

In yet another embodiment the present invention provides a multilayerdiaper structure employing a nonwoven polypropylene fabric having asingle fused side in the construction thereof.

In still another embodiment the present invention provides a sweatbandstructure for use in a hat.

In still another embodiment the invention provides a sweatband orwristband structure employing a nonwoven polypropylene fabric having asingle fused side in the construction thereof.

It is, therefore, an object of the present invention to provide animproved method of removing and transferring liquid from aliquid-bearing surface or the like.

Another object of the invention is to provide improved means forremoving and transferring liquid from a liquid-bearing surface.

Other objects and advantages of the present invention will be readilyapparent to those skilled in the art from a reading of the followingdetailed description and claims, together with the accompanying drawingsin which:

FIG. 1 is a perspective view of a piece of nonwoven fabric as empolyedin the present invention.

FIG. 2 is a partial, cross-sectional view of a moisture-absorbentbandage assembly constructed in accordance with the present invention;

FIG. 3 is a partial, cross-sectional view similar to FIG. 2 showinganother form of moisture-absorbent bandage assembly;

FIG. 4 is a partial, cross-sectional view showing one form ofmoisture-absorbent diaper assembly constructed in accordance with thepresent invention;

FIG. 5 is a partial, cross-sectional view similar to FIG. 4 showinganother form of moisture-absorbent diaper assembly;

FIG. 6 is a partial, cross-sectional view of a hat and hat sweatbandconstructed in accordance with the present invention; and

FIG. 7 is a perspective view of a moisture-absorbent headband or thelike constructed in accordance with the present invention with a portionthereof broken away to more clearly illustrate details of construction.

Referring now to the drawings, FIG. 1 shows a rectangular piece ofnonwoven fabric 10. The nonwoven fabric is preferably produced by themethod which comprises forming a batt or web comprising polypropylenefibers oriented primarily in the fill direction, drafting the batt inthe warp direction, needling the drafted batt to entangle the fibersdrafting the needled batt in both the warp and fill directions, andfusing one side of the resulting batt by suitable means such as infraredradiation. Such a process is disclosed in Platt et al., U.S. Pat. No.4,042,655, dated Aug. 16, 1977, the text of which is incorporated hereinby reference. The fabric 10 is preferably formed of nonwoven,polypropylene fibers in the form of staple or continuous filaments whichhave been drawn and needled to form a web or batt which is fused on oneside 12 thereof. The opposite side 14 of the fabric 10 is unfused andforms a relatively rough or fuzzy beard side of the fabric 10.

When the nonwoven polypropylene fabric, fused on one side and unfused onthe opposite side, is wetted, the moisture adsorbed on the unfused orbeard side migrates or wicks through the fabric toward the fused side of12.

Such a polypropylene fabric thus presents a dry or substantially drysurface to the touch on the unfused or beard side 14 and presents acomparatively wet surface to the touch on the fused side 12. Thus, thefabric 10, when suitably sterilized, provides an adsorbent means orstructure suitable for a bandage or bandage pad or compress which, whenplaced over a moisture-bearing surface, such as a wound, serves totransmit moisture such as body fluids contacted by the unfused beardside 14 of the fabric 10 away from the moisture-bearing surface to thefused side 12 of the fabric.

As shown in FIG. 2 there is illustrated in cross-section a bandagestructure or the like wherein the fabric 10 is secured or adhered bysuitable means to a backing strip 16 with the fused side 12 proximate tothe backing strip 16 and with the unfused side 14 directed away from thebacking strip. The backing strip 16 can suitably be constructed of amoisture-impervious sheet or the like which may be suitably constructedof a flexible plastic material such as polyethylene or polypropylene.Such structure can also be advantageously employed as a diaper with theunfused side of the fabric 10 in contact with the skin of the wearer.

The backing strip 16 can, if desired, be provided with perforations 18therein adjacent to the fused side 12 of the fabric to permit moistureaccumulating on the fused side to evaporate. The fabric 10 can besecured to the backing strip 16 by a suitable cement, or may be fusedthereto as shown at 20. The backing strip can be provided with asuitable adhesive 22 on the surface 24 thereof for securing the fabric10 in a desired position relative to a moisture-bearing surface.

FIG. 3 illustrates a structure slightly modified from that illustratedin FIG. 2 wherein a moisture-pervious sheet 26 is positioned over theunfused side 14 of the fabric 10 to provide a moisture-pervious barrierbetween the fabric 10 and a moisture-bearing surface, such as a wound,which barrier prevents the fabric from sticking to the wound. Thebacking strip 16 can again be provided with perforations 18 therein ifdesired. The sheet 26 can be suitably secured to the backing strip 16 bymeans of adhesive or the like as shown at 28.

Referring now to FIG. 4, a disposable diaper 30 is illustrated incross-section. The construction of the diaper 30 is characterized by theemployment of a suitably dimensioned piece of nonwoven fabric 10 whereinthe fused side 12 thereof is disposed in contact with the upper surface32 of a resilient foam layer 34, which foam layer is preferably ofcellular construction having elastomeric and wet-stable properties tofacilitate the conformation of the diaper about the legs and body of awearer. The foam layer 34 can be either hydrophilic or hydrophobic. Theunfused side 14 of the nonwoven fabric 10 is in contact with a suitablemoisture-absorbent core or batt 36 which may be suitably constructed ofa loosely compacted assemblage of cellulosic fibers. A moisture-perviousfacing sheet or layer 38 is positioned over the batt 36 and piece ofnonwoven fabric 10 and is secured to the upper surface 32 of the foamlayer 34 by suitable means such as an adhesive as shown at 40. Amoisture-impervious backing sheet 42 is disposed adjacent the lowersurface 44 of the foam layer 34 and is preferably secured thereto bysuitable means such as through the use of a suitable adhesive as shownat 46. The backing sheet 42 can be suitably formed of a relatively thinsheet of flexible plastic such as polyethylene or polypropylene.

The multilayer, disposable diaper 30, when properly positioned on thewearer, readily absorbs moisture through the moisture-pervious facingsheet 38 into the moisture-absorbent core 36, which moisture is thendrawn from the core 36 through the novel wicking action of the nonwovenfabric 10, such moisture accumulating along the fused side 12 thereof.

FIG. 5 illustrates a slightly modified disposable diaper structure whichis designated by the reference character 30a. The diaper 30a differsfrom the previously described diaper 30 in that a second piece ofnonwoven fabric 10 is disposed intermediate the lower surface 44 of thefoam layer 34 and the moisture-impervious backing sheet 42, with thefused side 12 of the second piece of fabric 10 adjacent the backingsheet 42 and with the unfused side 14 contacting the foam layer 34.

In both the diapers 30 and 30a, the pieces of nonwoven fabric 10 may beadhered to the foam layer 34 by suitable means such as an adhesive asshown in 48.

FIG. 6 illustrates a hatband or sweatband generally designated by thereference character 50 secured within and around the crown 52 of a hat54. The sweatband 50 comprises a strip of nonwoven fabric 10, asdescribed above, having the unfused side 14 thereof facing inwardly toengage the head of the wearer of the hat in moisture-conductingrelation. The fused side 12 of the fabric strip 10 is disposed adjacentthe inner surface of a moisture absorbent strip 56 in moistureconducting relation to facilitate the transfer of moisture to the strip56. The outer surface of the moisture-absorbent strip 56 is positionedagainst a substantially moisture-impervious backing sheet or strip 58which, in turn, contacts the inner surface of the crown 52. The loweredges of the strips 10, 56 and 58 comprising the sweatband 50 aresuitably secured about the lower periphery of the crown 52 by suitablemeans such as stitching as shown at 59.

FIG. 7 illustrates a novel headband or wristband structure generallydesignated by the reference character 60. The headband 60 comprises anonwoven polypropylene fabric strip 10 as described previously. Theunfused side 14 of the strip 10 faces inwardly to engage the skin of awearer in moisture-conducting relation, while the fused side 12 of thestrip 10 is disposed in contact with the inner surface of amoisture-absorbent outer strip 62, which can be suitably formed ofcotton terry cloth or the like, whereby moisture from the wearer's skinwicks or migrates from the unfused side 14 of the fabric strip 10 to thefused side 12, the moisture then being readily absorbed from the fusedside 12 by the moisture-absorbent strip 62. The opposite ends of theheadband 64 and 66 are provided with suitable means for securing theband 60 about the head of the wearer or, about the wrist of a wearer.Such suitable means includes conventional friction snaps as shown at 68.Alternately, suitable means for securing the ends 64 and 66 together canbe provided by a Velcro hook-and-eye connection or an elastic stretchband.

The newly discovered novel characteristic of the nonwoven polypropylenefabric 10 which renders the previously described structures advantageousfor their intended uses, is the capacity of the fabric, when subjectedto moisture, to present a substantially dry feeling on the beard orunfused side 14 thereof while the fused side 12 exhibits a substantiallywet feeling. This novel characteristic of the nonwoven polypropylenefabric 10 is apparently attributable to the capacity of polypropylenefibers to cause the wicking or migrating of moisture therethrough.However, until now it had not been known that a nonwoven polypropylenefabric having a fused surface on one side and an unfused surface on theopposite side exhibits the previously described wet and dry feeling. Ithas been found that nonwoven polypropylene fabric which is fused on oneside in response to the application of infrared heat thereto exhibitsthis characteristic in a most pronounced manner. For example, a fabricso constructed, made from polypropylene fibers of 3 denier ×3.25" (8.25cm) formed into a fabric weighing 3.5 oz/yard (82.6 grams/sq. meter) andfused on one side with infrared heat, exhibited the describedcharacteristics. However, nonwoven polypropylene fabric which is fusedon one side through other means such as the application of a heated rollthereto in the formation of the fabric exhibits the same characteristic.

It will be seen in each of the previously described structures in whichthe nonwoven polypropylene fabric 10 is employed that this unique andnewly discovered characteristic of the fabric 10 is advantageouslyemployable in a number of practical applications such as the manufactureof bandage pads or compresses, bandages, disposable diapers, hatsweatbands, headbands, and wristbands, etc. wherein it is advantageousto conduct moisture away from a moisture-bearing surface such as awound, the perineal region of an infant, the skin and hair of the wearerof a hat and the perspiration laden skin and hair of a perspiringindividual, and maintain the moisture separated from themoisture-bearing surface.

Reasonable variations and changes may be made in the construction andarrangement of parts or elements of the various embodiments as disclosedherein without departing from the spirit and scope of the invention asdefined in the following claims.

What is claimed is:
 1. A method of transferring liquid from aliquid-bearing surface, comprising:positioning a nonwoven fabriccomprising a plurality of staple polypropylene fibers including aplurality of unfused polypropylene fibers on a first side thereof and asecond plurality of fused polypropylene fibers on a second opposite sidethereof with at least a portion of the unfused fibers of the first sidein contact with the liquid on the liquid-bearing surface; and allowingthe liquid from the liquid-bearing surface to migrate through theunfused fibers to the fused fibers on the second side of the nonwovenfabric.
 2. A method in accordance with claim 1 wherein saidpolypropylene fibers comprise staple fibers.
 3. A method in accordancewith claim 1 wherein said polypropylene fibers comprise continuousfibers.
 4. A method in accordance with claim 1 wherein saidpolypropylene fibers are staple fibers.
 5. A method in accordance withclaim 1 wherein said nonwoven fabric is positioned in contact with theliquid with a moisture-pervious layer interposed between said nonwovenfabric and the liquid-bearing surface.
 6. A method in accordance withclaim 1 or claim 5 wherein the liquid-bearing surface is the skin of aliving being.
 7. A method of transferring liquid from a liquid-bearingsurface, comprising:positioning a nonwoven fabric comprising a pluralityof polypropylene fibers including a plurality of unfused polypropylenefibers on a first side of said nonwoven fabric and a second plurality offused polypropylene fibers on a second opposite side of said nonwovenfabric with at least a portion of the unfused fibers of the first sidein liquid flow communication with the liquid on the liquid-bearingsurface; and allowing the liquid thus communicating with the unfusedfibers to migrate through the unfused fibers to the fused fibers on thesecond side of said nonwoven fabric.
 8. A method in accordance withclaim 7 wherein a moisture-pervious sheet is interposed between saidnonwoven fabric and the liquid-bearing surface prior to the positioningstep.
 9. A method in accordance with claim 8 wherein amoisture-absorbent core is interposed between said moisture-pervioussheet and the first side of said nonwoven fabric prior to thepositioning step.
 10. A method in accordance with claim 1 or claim 7characterized further to include removing liquid from the second side ofthe nonwoven fabric.
 11. A method in accordance with claim 7 whereinsaid polypropylene fibers are staple fibers.